I might be a bit late on this one, but we cant eat dairy in our family either.
I use almond milk/coconut milk to replace the milk in recipes cup for cup, if buttermilk is called for then i do the same method to make regular milk into buttermilk(adding vinegar or lemon juice to the milk) only i use almond milk. it works awesome! it also comes in vanilla and chocolate, yum!
for butter i use coconut oil cup for cup also, you can get a couple varieties, some still have the coconut taste and some dont, i use either one depending on the flavor of my cake/baking. Hope that helps, living without dairy is kinda tough unless you get creative lol